1. Field of the Invention
The invention relates to an optical disk drive, and more particularly, to an optical disk drive for avoiding the event of a flying disk.
2. Description of the Prior Art
Optical disks have become one of the most important storage media in modern society because of their compact size, low cost, and high storage capacity. Optical disks are played by optical disk drives. An optical disk is fixed by a holder in an optical disk drive and rotated so that a pickup head of the drive can search for data on the disk. During high speed rotation, the optical disk may no longer be strictly fixed on its position due to vibration or shock to the drive in an event that is called a “flying disk”. To prevent a flying disk event, a typical disk drive uses a magnetic holder to hold the disk.
Please refer to FIG. 1 showing a conventional optical disk drive 10 using a magnetic holder. The disk drive 10 includes a holder 12, a tray 14, a protrusion 16, a turn table 18, and a motor 20. The holder 12 is movably installed on the upper part of the disk drive, the tray 14 is movably installed between the holder 12 and the turn table 18, the protrusion 16 includes a magnet 24, the motor 20 is installed under the turn table 18, and an optical disk 22 is put on the tray 14. When reading the disk 22, the turn table 18 pushes the disk 22 up so that the disk 22 is brought up from the tray 14 and clipped between the turn table 18 and the holder 12, and then the motor 20 rotates the turn table 18 for a pickup head of the disk drive 10 to read the disk 22. The holder 12 is made of metal and installed above the tray 14 for clipping the disk 22 in cooperation with the turn table 18.
To repeat, when reading the disk 22, the turn table 18 goes up to bring the disk 22 up from the tray 14 and clip the disk 22 in cooperation with the holder 12; at this moment the magnet 24 included in the protrusion 16 on the turn table 18 becomes close enough to the holder 12 so that the holder 12, which is made of metal, is attracted downwards by the magnet 24, strictly clipping the disk 22. By moving the magnet 24 up and down, the holder 12 can be controlled to adhere to or depart from the turn table 18.
As described above, the prior art installs the magnet 24 in the protrusion 16 to attract the holder 12 in order to adhere the holder 12 to the turn table 18 so that the holder 12 and the turn table 18 can strictly clip the disk 22 to prevent flying disk due to shock and collision during high speed rotation. However, the attraction of the magnet decreases as the temperature increases. As the temperature increases, the attraction of the magnet may decrease to the point where it can no longer attract the turn table 18. In this case, the possibility of a flying disk event occurring is strong.